What is the sound of 727 horses at full gallop? In Roush’s P-51 Mustang, the answer is up to you. While there are plenty of performance vehicles that have adjustable exhaust notes, not many can do so via a smartphone app. A couple years ago, Roush introduced an Active Exhaust program for iOS that does exactly that, and it’s featured on Roush’s new 727-hp P-51, its most powerful Mustang yet.
Those who know aircraft history will already have noticed that Roush’s new model is named...